Primaquine

Indications

Primaquine is used for: Malaria

Adult Dose

Oral Prevention of relapse of P. vivax malaria 30 mg PO qDay for 14 days Uncomplicated P. vivax and P. ovale malaria 30 mg PO qDay for 14 days with chloroquine or hydroxychloroquine Alternatively, for mild G6PD deficiency or as alternative to daily regimen: 45 mg PO qDay for 8 weeks (only to be used after consultation with an infectious disease/tropical medicine expert Chemoprophylaxis P. vivax and P. ovale maleria: 30 mg PO qDay for 14 days after departure from malaria-endemic area

Child Dose

Oral Uncomplicated P. vivax and P. ovale malaria 0.5 mg/kg (30 mg/day maximum) qDay for 14 days with chloroquine or hydroxychloroquine Chemoprophylaxis 0.5 mg/kg PO qDay (30 mg/day maximum); start 1-2 days prior to travel and continue for 7 days after departure from malaria endemic area

Renal Dose

Administration

Should be taken with food. Take w/ meals to avoid GI discomfort.

Contra Indications

Hypersensitivity. Childn <1 yr. Acute flare-ups of systemic diseases (RA, SLE) having tendency for agranulocytopaenia, Pregnancy and lactation.

Precautions

G6PD deficiency; pregnancy; NADH methaemoglobin reductase deficient patients. Monitor Hb levels and blood counts routinely. Patients with systemic diseases that have an increased risk of granulocytopenia. Withdraw treatment if signs of haemolysis or methaemogloinaemia occur.

Pregnancy-Lactation

Pregnancy Contraindicated in pregnant women; even if a pregnant woman is G6PD normal, the fetus may not be; safe usage in pregnancy not established; use during pregnancy should be avoided except when in judgment of the physician benefit outweighs possible hazard Sexually-active females of reproductive potential should have a pregnancy test prior to starting primaquine Contraception Advise females of child bearing potential to use effective contraception (methods that result in less than 1% pregnancy rates) when receiving therapy and after stopping treatment until completion of an ongoing ovulatory cycle (eg, up to next menses) Advise treated males whose partners may become pregnant, to use a condom while on treatment and for 3 months after stopping treatment Lactation CDC recommends do not use in nursing women unless breast-fed infant has been determined not to have G6PD deficiency

Interactions

Primaquine may inhibit metabolism of chloroquine. Avoid ethanol. Potentially Fatal: Mepacrine may potentiate toxicity of primaquine. Potentially haemolytic drugs eg, sulphonamides, nitrofurans and bone marrow suppressants eg, methotrexate, phenylbutazone, chloramphenicol should not be co-admin with primaquine.

Adverse Effects

Side effects of Primaquine : >10% Abdominal pain, Hemolytic anemia in G6PD deficiency, Nausea, Vomiting <1-10% Methemoglobinemia in NADH-methemoglobin reductase-deficient individuals <1% Agranulocytosis, Arrhythmias, Headache, Interference with visual accommodation, Leukopenia, Leukocytosis, Rash, Dizziness, Pruritus Potentially Fatal: Haemolytic anaemia (G6PD deficient), thrombocytopaenia, leucopaenia, AV block.

Mechanism of Action

Primaquine is an 8-aminoquinoline antimalarial which eliminates the exoerythrocytic forms of malarial parasite P.vivax, P. falciparum by disrupting mitochondria and binding to DNA. By this action primaquine achieves radical cure of vivax malaria. It is also active against gametocytes of P.falciparum.